Design method for the number of protrusions in air-blown optical cables and air-blown optical cables

Abstract

This invention provides a method for designing the number of protrusions in an air-blown optical cable. The air-blown optical cable includes a cable core and an outer sheath. The outer sheath includes a sheath body and a plurality of protrusions arranged in an array around the sheath body. The air-blown optical cable is used to lay within an air-blowing duct. The range of protrusion numbers is calculated based on the distance from the axis of the air-blown optical cable to the end of the protrusion, the distance from the axis of the air-blown optical cable to the root of the protrusion, the radius of the air-blowing duct, the difference between the protrusion furthest from the air-blowing duct and the protrusion in the middle that contacts the air-blowing duct, the distance from the protrusion furthest from the air-blowing duct along the contact direction to the air-blowing duct, the radius of curvature of the protrusion, and the maximum half-width of the contact between the protrusion in the middle and the air-blowing duct. This invention's method for designing the number of protrusions in an air-blown optical cable and the air-blown optical cable itself allows for the calculation of the range of protrusion numbers, eliminating the need for experimental verification steps, saving experimental costs, simplifying the verification process, and shortening the production cycle.

Description

Technical Field

[0001] This invention relates to a method for designing the number of protrusions in an air-blown optical cable and to an air-blown optical cable. Background Technology

[0002] Air-blown optical cables, due to their ability to rapidly deploy in urban underground pipe networks, long-distance pipelines, and complex terrains by combining the blowing force of compressed air with the thrust of a transmission device, are widely used in modern communication network construction. To address the frictional damage caused by the optical cable against the pipe wall during high-speed air blowing, traditional designs typically incorporate air guide grooves or elastic protrusions on the cable's outer surface. This design reduces contact pressure through airflow guidance and buffers localized stress through elastic deformation, while simultaneously reducing contact area, optimizing blowing efficiency, and protecting the cable itself. It is noteworthy that the parameter design of these air guide structures requires comprehensive consideration of multiple factors, including the material's elastic modulus, the roughness of the pipe's inner wall, and the air blowing pressure; their performance directly impacts construction efficiency and the cable's lifespan.

[0003] However, in existing technologies, the number and distribution of protrusions mainly rely on the experience and judgment of designers, typically employing a "design-then-test" model for verification. Specifically, designers need to initially determine the protrusion parameters based on empirical formulas, followed by mold making, sample trial production, and air-blowing simulation tests. If the test results are unsatisfactory, the parameters need to be readjusted and the above process repeated. This traditional development model has significant drawbacks: First, the parameter selection lacks theoretical support, easily leading to a mismatch between the flow guiding structure and actual working conditions; second, from design to verification, it requires multiple stages such as mold making, trial production, and testing, with a single iteration cycle lasting several months, involving high equipment and mold costs and human resource investment; finally, existing designs only consider the air-blown optical cable itself, without considering the corresponding air-blowing pipe, which significantly increases the risk of technology transfer and market competition pressure.

[0004] In view of this, it is necessary to improve the existing design method for the number of protrusions in air-blown optical cables in order to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for designing the number of protrusions in an air-blown optical cable, so as to solve the problem that existing protrusion designs require experimental verification of the air-blowing effect.

[0006] To achieve the above objectives, this invention provides a method for designing the number of protrusions in an air-blown optical cable. The air-blown optical cable includes a cable core and an outer sheath. The outer sheath includes a sheath body and a plurality of protrusions arranged in an array around the sheath body. The air-blown optical cable is used to be laid inside an air-blowing duct. The number of protrusions in the axial section of the outer sheath is [number missing]. N , N are integers and satisfy N≥ N min , ,in , It is half the angle between two adjacent convex teeth. R 齿尖 This is the distance from the axis of the air-blown optical cable to the end of the protruding tooth. R 齿根 This is the distance from the axis of the air-blown optical cable to the root of the tooth. R 管 The radius of the air blowing pipe.

[0007] As a further improvement to the present invention, the number of teeth N satisfy N ≤ N max ,in ,in N 间隔 This is the difference between the farthest tooth that contacts the air purging pipe and the middle tooth that contacts the air purging pipe. The distance between the farthest protrusion in contact with the air blowing pipe and the air blowing pipe along the contact direction. Equal to the deformation of the convex tooth in contact with the air blowing pipe in the middle , , R 凸 Let be the radius of curvature of the tooth. b The maximum half-width of the contact between the protruding tooth in the middle and the air blowing pipe.

[0008] As a further improvement of the present invention b The calculation formula is as follows: ,in F / L Contact force per unit length F For gravity, L The length of the air-blown optical cable. E * For the equivalent elastic modulus, R * denoted as the relative radius of curvature.

[0009] As a further improvement of the present invention E * The calculation formula is as follows: ,in E 凸 The Young's modulus of the convex teeth. v 凸 For the Poisson's ratio of the convex teeth, E 管 For the Young's modulus of the air-blown pipe, v 管 This is the Poisson's ratio for the air-blowing pipe.

[0010] As a further improvement of the present invention, the protruding teeth are made of the same material as the sheath body, namely HDPE high-density polyethylene. E 凸 500-1500MPa v 凸 It is 0.35-0.45.

[0011] As a further improvement of the present invention R * The calculation formula is as follows: ,in R 凸 Let be the radius of curvature of the tooth. R 管 The radius of curvature of the air-blowing pipe.

[0012] As a further improvement of the present invention N 间隔 =3.

[0013] As a further improvement to the present invention, tooth height , H : R 齿根 The ratio is 1:40 to 1:20.

[0014] The present invention also provides an air-blown optical cable, the air-blown optical cable including a cable core and an outer sheath, the outer sheath including a sheath body and a plurality of protrusions arranged in an array around the sheath body, the number of protrusions being obtained by the protrusion number design method of the air-blown optical cable as described above.

[0015] The beneficial effects of the present invention are: the design method for the number of protrusions in the air-blown optical cable and the air-blown optical cable of the present invention can obtain the range of the number of protrusions by calculation, which can save the experimental verification steps, save experimental costs, save the verification process, and shorten the production cycle. The air-blown optical cable obtained by the method can be quickly put into production and use, thereby improving product competitiveness. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0017] Figure 1 This is a schematic diagram of the air-blown optical cable of the present invention being laid in an air-blown pipe;

[0018] Figure 2 This is a schematic diagram showing the contact between multiple protrusions of the air-blown optical cable of the present invention and the air-blowing pipe.

[0019] Figure 3 This is a schematic diagram showing a tooth of the air-blown optical cable of the present invention in contact with the air-blowing pipe.

[0020] Figure 4 This is a schematic diagram showing a protruding tooth of the air-blown optical cable of the present invention contacting the air-blowing pipe and undergoing deformation.

[0021] Figure 5 This is a partially enlarged schematic diagram of the air-blown optical cable and multiple protruding teeth in contact with the air-blown pipe of the present invention. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] like Figures 1 to 5 As shown, the air-blown optical cable of the present invention includes a cable core and an outer sheath. The outer sheath includes a sheath body and a plurality of protrusions arranged in an array around the sheath body. The air-blown optical cable is used to be laid in an air-blowing pipe. The range of the number of protrusions is obtained by the protrusion number design method of the air-blown optical cable of the present invention.

[0026] like Figure 1As shown, in this embodiment, the number of teeth along the axial section of the outer sheath is set to... N Furthermore, the protruding teeth surround the outer sheath in a circular array, with equal spacing between adjacent protruding teeth. N are integers and satisfy N min ≤ N ≤ N max .

[0027] ,in , It is half the angle between two adjacent convex teeth. R 齿尖 This is the distance from the axis of the air-blown optical cable to the end of the protruding tooth. R 齿根 This is the distance from the axis of the air-blown optical cable to the root of the tooth. R pipe The radius of the air purging pipe. When N The value of is approximately close to N min This indicates that the protruding teeth are relatively sparse.

[0028] calculate The formula is obtained as follows: See Figure 1 Taking the extreme case, in which two adjacent protrusions are in contact with the air-blowing pipe, and the sheath body between the two protrusions is in contact with the air-blowing pipe, the following formula is satisfied: ; ,in The angle between the axis of the air-blowing pipe and the two protruding teeth that contact the air-blowing pipe is half of the angle between them, from which the following can be derived: .if N Less than N min If the teeth are too sparse, the sheath body will come into contact with the air blowing pipe during the air blowing process, which will bring at least the following disadvantages: (1) the sheath body comes into contact with the air blowing pipe and the teeth cannot play a supporting role; (2) the air flow gap between the outer sheath and the air blowing pipe is reduced; (3) the contact area between the outer sheath and the air blowing pipe is too large, resulting in increased friction; (4) the sheath body directly contacts the pipe, causing wear and affecting the service life of the air-blown optical cable.

[0029] If calculated N min If it is not an integer, then N Accordingly, round up. In this embodiment, N Design greater than N min This ensures that the sheath of the air-blown optical cable will not come into contact with the air-blowing pipe during the laying process, thus improving laying efficiency.

[0030] In addition, in this embodiment, the tooth height , H : R 齿根 The ratio is 1:40 to 1:20. Under this design, as long as it ensures... N min ≤ N In this way, the laying effect of air-blown optical cables can be fully guaranteed.

[0031] This embodiment of the test is an air-blowing test. The optical cable is laid using air-blowing within a 1500m long air-blowing duct. The required blowing speed is 0 to 60m / min. If the laying can be completed within 50 minutes, it meets the requirements, and the test result is successful. If the air-blowing time exceeds 50 minutes, it does not meet the requirements, and the test result is unsuccessful. The test results for the minimum number of teeth are as follows:

[0032]

[0033] The above test data shows that when the designed number of teeth... N Greater than the calculated number of teeth N min The air blowing test results of the embodiments were all successful, and the designed number of teeth N Less than the number of teeth to be calculated N min The air blowing test results of the embodiments all failed.

[0034] like Figures 2 to 5 As shown, ,in N 间隔 This is the difference between the farthest tooth that contacts the air purging pipe and the middle tooth that contacts the air purging pipe. The distance between the farthest protrusion in contact with the air blowing pipe and the air blowing pipe along the contact direction. Equal to the deformation of the convex tooth in contact with the air blowing pipe in the middle , , R 凸 Let be the radius of curvature of the tooth. b The maximum half-width of the contact between the protruding tooth in the middle and the air blowing pipe.

[0035] Maximum number of teeth N max The main consideration is the number of contacts between the teeth and the air blowing pipe. If the teeth are too dense, it may result in too many contacts between the teeth and the air blowing pipe, thereby increasing the contact area and increasing friction.

[0036] If, through testing, six or seven protruding teeth come into contact with the air blowing pipe, the air blowing effect is poor.N 间隔 The value is 3; if four or five protruding teeth are in contact with the blowing pipe, the air blowing effect will be poor. N 间隔 The value is 2, meaning the number of teeth affecting the air blowing effect needs to be determined experimentally. N 摩擦 , or ,See N 摩擦 The parity determination, the former applies to N 摩擦 For the case where the number is even, the latter applies. N 摩擦 In the case of an odd number, this embodiment uses... N 摩擦 Examples are given for odd numbers.

[0037] In this embodiment, N 间隔 =3. Multiple tests have shown that when the number of protrusions in contact with the air blowing pipe is 7 or more, the air blowing effect is extremely poor.

[0038] When one of the protruding teeth of the air-blown optical cable just comes into contact with the air-blown pipe, and the axial connection direction between the air-blown optical cable and the air-blown pipe is set to the h direction, the protruding tooth has not deformed at this time, and the distance between it and the contacting protruding tooth is... N 间隔 The number of protruding teeth and the distance along the h-direction of the air blowing pipe are When the air-blown optical cable is pressed against the air-blown pipe, the protruding teeth in contact with the air-blown pipe deform. ,if = Then set the number N 摩擦 Contact with the air blowing pipe.

[0039] and ,in b The calculation formula is as follows: ,in F / L For contact force per unit length, more specifically, F For gravity, L The length of the air-blown optical cable. E * For the equivalent elastic modulus, R * The relative radius of curvature. The contact half-width is derived from the Hertzian pressure distribution model. b ,satisfy ,in x Represents the horizontal direction of the contact plane. x=0 represents the contact center.

[0040] E The formula for calculating * is as follows: ,in E 凸 The Young's modulus of the convex teeth. v 凸 For the Poisson's ratio of the convex teeth, E 管 For the Young's modulus of the air-blown pipe, v 管 This is the Poisson's ratio for the air-blowing pipe.

[0041] R * The calculation formula is as follows: ,in R 凸 Let be the radius of curvature of the tooth. R 管 The radius of curvature of the air-blowing pipe.

[0042] The protruding teeth are made of the same material as the sheath body, namely HDPE high-density polyethylene. E 凸 500-1500MPa v 凸 It is 0.35-0.45.

[0043] Currently, some air-blowing pipes used in actual production are also made of HDPE (high-density polyethylene), whose E 管 700-1500MPa v 管 It ranges from 0.33 to 0.43.

[0044] Number of protrusions in this embodiment N The design, in addition to considering the properties of the air-blown optical cable itself, also takes into account the characteristics of the air-blown pipe in the actual application scenario.

[0045] The test results for the maximum number of teeth are as follows:

[0046]

[0047] The above test data shows that when the designed number of teeth... N Less than the number of teeth to be calculated N max The air blowing test results of the embodiments were all successful, and the designed number of teeth N Greater than the calculated number of teeth N max The air blowing test results of the embodiments all failed.

[0048] The design method for the number of protrusions in the air-blown optical cable and the air-blown optical cable of the present invention can obtain the range of protrusion numbers through calculation, which can eliminate the need for experimental verification steps, save experimental costs, eliminate the verification process, and shorten the production cycle. The air-blown optical cable obtained by this method can be quickly put into production and use, thereby improving product competitiveness.

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for designing the number of protrusions in an air-blown optical cable, the air-blown optical cable comprising a cable core and an outer sheath, the outer sheath comprising a sheath body and a plurality of protrusions arranged in an array around the sheath body, the air-blown optical cable being laid inside an air-blowing duct, characterized in that: The number of teeth along the axial section of the outer sheath is N, where N is an integer and satisfies... N ≥ N min , ,in , It is half the angle between two adjacent convex teeth. R 齿尖 This is the distance from the axis of the air-blown optical cable to the end of the protruding tooth. R 齿根 This is the distance from the axis of the air-blown optical cable to the root of the tooth. R 管 The radius of the air blowing pipe.

2. The method for designing the number of protrusions in an air-blown optical cable according to claim 1, characterized in that: Number of teeth N satisfy N ≤ N max ,in ,in N 间隔 This is the difference between the farthest tooth that contacts the air purging pipe and the middle tooth that contacts the air purging pipe. The distance between the farthest protrusion in contact with the air blowing pipe and the air blowing pipe along the contact direction. Equal to the deformation of the convex tooth in contact with the air blowing pipe in the middle , , R 凸 Let be the radius of curvature of the tooth. b The maximum half-width of the contact between the protruding tooth in the middle and the air blowing pipe.

3. The method for designing the number of protrusions in an air-blown optical cable according to claim 2, characterized in that: b The calculation formula is as follows: ,in F / L Contact force per unit length F For gravity, L The length of the air-blown optical cable. E * For the equivalent elastic modulus, R * denoted as the relative radius of curvature.

4. The method for designing the number of protrusions in an air-blown optical cable according to claim 3, characterized in that: E * The calculation formula is as follows: ,in E 凸 The Young's modulus of the convex teeth. v 凸 For the Poisson's ratio of the convex teeth, E 管 For the Young's modulus of the air-blown pipe, v 管 This is the Poisson's ratio for the air-blowing pipe.

5. The method for designing the number of protrusions in an air-blown optical cable according to claim 4, characterized in that: The protruding teeth are made of the same material as the sheath body, namely HDPE high-density polyethylene. E 凸 500-1500MPa v 凸 It is 0.35-0.

45.

6. The method for designing the number of protrusions in an air-blown optical cable according to claim 3, characterized in that: R * The calculation formula is as follows: ,in R 凸 Let be the radius of curvature of the tooth. R 管 The radius of curvature of the air-blowing pipe.

7. The method for designing the number of protrusions in an air-blown optical cable according to claim 2, characterized in that: N 间隔 =3。 8. The method for designing the number of protrusions in an air-blown optical cable according to claim 1, characterized in that: Tooth height , H : R 齿根 The ratio is 1:40 to 1:

20.

9. An air-blown optical cable, characterized in that: The air-blown optical cable includes a cable core and an outer sheath. The outer sheath includes a sheath body and a plurality of protrusions arranged in an array around the sheath body. The number of protrusions is determined by the protrusion number design method of the air-blown optical cable as described in any one of claims 1-8.

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